Wild Turkey Population Swings

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- Hi, Sanford Smith here with Penn State Extension.

Today I'm joined by Duane Diefenbach who's a wildlife biologist with the Pennsylvania Cooperative Fish and Wildlife Research Unit of USGS.

And he works in conjunction with the Pennsylvania Game Commission as well as Penn State University.

Duane, we're gonna talk today a little bit about the factors that influence turkey sightings or turkey abundance, turkey survival in Pennsylvania.

Many people tell me, oh, the turkey are down this year and then the next year, oh, they're up.

And they get confused because they see turkeys more on some years or sometimes a year and then they don't at other times.

So, can you talk a little bit about those factors?

- Sure, first of all, there are many more turkeys than there were a hundred years ago because of the efforts of the Game Commission to trap and transfer turkeys and establish populations so that they're now common, pretty common across most of the Commonwealth.

Populations do vary, and part of that is because of the life history of wild turkeys.

They have very high reproductive rates.

They'll have a clutch of 12 to 14 eggs, but they also have very high mortality rates.

So during the springtime, males experience a lot of mortality.

Some of it due to hunting, but also just due to predators because they're gobbling and very visible trying to attract mates and that makes 'em more susceptible to being killed by predators.

- [Sanford] Yeah, they're a little lovesick, aren't they?

And they're not paying attention maybe to the predators.

- It's a risky behavior, right?

And then later on when females are nesting and on the nest, they're at greater risk of mortality because of their sitting still in one place.

And there many different predators eat turkeys.

So you see very high mortality rates during that time of the year.

- If you consider the egg, the protected egg, a turkey then you have high mortality rates on the nests.

- [Duane] Nests can get predated.

The young turkeys, they're susceptible to predation because they cannot fly, and until they can fly and roost into a tree, they're at risk.

So that's why turkeys produce lots of eggs.

- What about weather?

How does that influence turkeys in the fall and in the spring?

- Weather probably has the greatest influence on the survival of young.

So studies have shown that when you have a cool, wet spring you tend to have lower reproduction so fewer of those chicks actually survive.

- Yeah. What about in the fall?

Any kind of fall weather patterns that are particularly impactful on turkey populations?

- Not so much on survival.

I think in the fall, what influences our perception of how many turkeys there are, is the abundance of acorns.

So when we have a high mast year where the oaks are producing lots of acorns, the turkeys will be dispersed.

We actually see lower harvest rates in the fall hunting season because of that, because they're so dispersed it's harder to find turkeys.

And then when you have a year with very little mass production, turkeys tend to be more concentrated.

They're a little more visible to people and they're also a little more susceptible to hunting.

So we see slightly higher harvest rates during years with low mast.

- And I know you've been doing some research related to turkeys.

Just in a nutshell, what kind of work are you doing?

- Well, the objective is to identify how we can make a decision to set fall hunting seasons because as I mentioned, when we have cool, wet springs, we have low recruitment so we want to have a more conservative hunting season.

So really our work is to try and better understand how we can predict fall turkey populations to set fall hunting seasons.

- Okay, so hunting is the tool for wildlife management, isn't it for turkeys, in many respects.

Duane, I wanna thank you very much for joining me today.

And this is interesting, knowing more about why turkey populations seem to go up and down.

Sometimes I guess they actually do and other times it's just our perception.

Thanks very much for joining us today.

- Oh, you're welcome.